Answer: The answer is Acetabulum.
Explanation: The Acetabulum is formed from the three pelvic bones,ilium,ischium and pubis.
the Acetabulum is cuped-shaped or socket-like and found by the side of the pelvis.it forms the hip joint by joining with the head of the femur.
The Acetabulum together with the hip joint allows us to run,walk and move freely.